<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    function Work() {
        this.info = function () {
            console.log('作业类型：卸货、酒水、配送... ')
        }
    }

    function Unload() {
        this.bulk = function () {
            console.log("卸货重量: 0.5吨")
        }
    }

    Unload.prototype = new Work()

    var unload_jack = new Unload() // 卸载员
</script>
</body>
</html>
